Ignition device for internal-combustion engines



APPLICATION FILED APR-2. I921.

Patented Oct. 4, 1921.

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F. A. SMITH. IGNITION DEVICE FOR INTERNAL COMBUSTION ENGINES,

APPLICATION FILED APILZ, 192l- Patented Oct. 4, 1921.

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. FREDERICK ARTHUR PATENT OFFICE.

SMITH, 0F BRASTED, ENGLAND.

IGNITION DEVICE FOR INTERNAL-COMBUSTION ENGINES.

Application filed April 2,

To all whom it may concern: V

Be it known that I, FREDERICK AR/THUR SMITH, a subject of the King ofEngland, residingat Brasted, Kent, England, haveinvented certain new anduseful Improvements in I nition Devices for Internal-Combustion ngines,(for which I have filed an application in England Jan. 7, 1920, PatentNo. 600,120,) of which the following is a specification.

This invention is for improvements in or relating to ignition devicesfor internalcombustion engmes of the type comprising an ignition orfiring chamber provided with an electric igniter, and having at itsinner end an inlet for an auxiliary ignition charge of explosivemixture, and terminating at its outer end in a spout or flame nozzleextending toward or into the main combustion chamber of an engine.

Ignition devices of the type referred to have been proposed but in allof such proposals the ignition or firing chamber is provided with asparking-plug either at its inner end or approximately midway along itslength, and is shaped like a bottle with a neck-that is narrow inrelation to the diameter of its body. In such a construction there is anabrupt change of diameter where the neck joins the body of the chamber.Consequently, when compression takes place in the cylinder andcompressed gases from the cylinder are forced through the narrow neck,violent turbulence ofthe gas or and effectively 'IIllX with themselvesan ignitible charge that has been admitted into the inner end of thechamber. 'Under some conditions such a mixture cannot be readily 1gnitedby the igniter.

This invention has for its main object to obviate this defect and toprovide a construction wherein an ignitible charge admitted to a part ofthe firing chamber surrounding the igniter shall remain surrounding theoperative part of the igniter while the gases from the cylinder arebeing compressed into'the chamber.

According to the present invention an ignition device of the typedescribed for internal-combustion engines is characterized by the factthat the ignition or firing (chamber, or a portion thereof, 1s soconstructed and shaped'as to form a pocket or space for accommodatingthe igniter points, which pocket or space is of regulartubular forma-Specification of Letters Patent.

Patented Oct. 4, 1921.

1921. Serial No. 458,059.

tion'without an abrupt expansionimmediately behind the outlet orifice,and it and the remainder of the ignition or firing chamber are of suchproportions and shape, and so situated, relatively to each other and tothe main combustion chamber of the engine that, during compression, onlythe auxiliary ignition charge is compressed Stratified around theigniter points, no turbulence being set up during such compression todisplace the auxiliary ignition charge clear from the igniter points. Byadopting such a construction, it will be insured that the ignitioncharge will be in a position to be ignited first and thus serve itsproper purpose. If, how- .ever, the volume capacity of the firingchamber is limited to such a degree that the compressed auxiliarv chargeis insufiicient to insure that the igniter points shall be imviously itsutility will be destroyed. It is also important that any additionalspace constituted by a recess in-the sparking-plug or device should beborne in mind in calculating the volume of the pocket for the igniter.

For a more complete understandin' the invention there will now bedescrilo by way of example only and with reference to the accompanyingdrawings, certain construbtional forms of ignition device according tothe present invention. It is to be understood, however, that theinvention is not limited to the precise constructional detailsillustrated.

In these drawings:- fFigure 1 is a sectional view through one form ofignition device in which there is shown a sparking-plug with a recessaround its sparking points; 7

Fig. 2 is a similar view of a modified construction embodying asparking-plug without such a recess;

Fig. 3 is a sectional view through a construction particularly suitablefor use with large engines, an

Fig. 4 is a section ficat'ion.

Like reference numerals indicate like parts throughout the drawings.

Inthe construction shown in Fig. l-the ignition device comprises apassage 10 which is of larger cross section at its ends than toward itsmiddle. One end 11 expands toward the engine cylinder thus forming akind of bell mouth to emit a large spread through a further modiof ed,

'- ward its end 11 adjacent the duit 14 to the inlet 15 which has a ballvalve 16. The sparking plug points are illus-' trated at 17 and 18 andaround the former the sparking plug is formed with a recess 19, thisbeing a well-known type of sparking plug. The expanded end 12 of thepassage 10, together with the conduit 14: and

' recess 19 constitute in this construction the pocket or spaceaforesaid in which the aux.- iliary ignition chanrge is compressedaround the igniter. In this figure the ignition charge is illustrateddiagrammatically in the position it will occupy during compression andimmediatelybefore ignition, by a series of dots. The remainder of thepassage 10 will be occupied by the contents of the main enginecombustion chamber. The volume of this pocket or space around theigniting points and the volume of the space extending away from theigniter toward the engine cylinder are so proportioned relatively toeach other and to the main combustion chamber of the engine, and thewalls of these spaces are so shaped, that during compression the mainengine charge, or exhaust gases left in the engine cylinder, will beunable to reach such igniting points. Thus the auxiliary ignition chargewill be in a position to be ignited first and thus serve its properpurpose.

1 the construction shown in Fig. 2 the ignltion or firing chamber 10contracts toengine cylinder. At its other end it is fitted with an inletvalve 20 and close to this latter with a sparking plug 13. In thisconstruction the pocket or space into which the ignition charge is.

to be compressed is constituted by the large end 12 of the chamber 10and an enlarged portion 21 of this chamber.

In the construction shown in Fig. 3 the igniter 13 and inlet valve 20are arranged c ose together at the inner end of a comparatively narrowtubular its other end opens into a larger box or chamber 23 whichcommunicates withflame nozzle 24. This enlarged chamber 23 is suitablefor receiving a large auxiliary ignition "charge for use in big engines.

'In Figs. 1 and 2 the ignition chamber takes the form of a straightnarrow passage and this is in some instances advantageous but it is notessential as in other constructions, as for instance that shown in Fig.4, the chamber may take the form of a curved conduit 25 o'penlng at oneend into a flame nozzle 26 and having at its other end the inlet valve16 and igniter 13. H

In another construction the ignition chamber maybe of tubular shape asat 22 in Fig.

ing at the other end into a flame nozzle incates with the flame nozzle.

pocket 22 which at igniter and openstead of, as shown in Fig. 3, into anenlarged chamber 23, which itself communi- In this construction ofignition device the tubular ignition chamber may be parallelthroughoutits length except .for the portion immediately adjacent the flamenozzle, where it may be gradually contracted to a small'extent.Furthermore, in such a construction the, parallel tubular portion of theignition chamber may be occupied by a solid member having tacts with theinner walls of the ignition chamber one or more helicalpassages leadingfrom end to end of such member, namely from near the igniter to near theflame nozzle.

.Many other constructions may be adopted without departing from thespirit and scope of the invention, and it is to be understood that theuse of the ignition device according to the present invention is notrestricted to any particular type of main charge, the essential pointbeing that the igniter points are arranged in a ocket or other portionof the ignition cham er which pocket or, other chamber portion, and theremainder of the ignition or firing chamber, are of such dimensions andshape, and so situated, relatively. to each other and to the maincombustion space of the engine that during com- .pression the auxiliaryignition charge is .compressed around,

to 1secure by Letters invention and desire atent 1s An ign tion devicefor internal-combustion engines comprising an ignition chamber, anelectric igniter therein, an inlet at the inner end of the chamber foran auxiliary i ition charge of explosive mixture, and a ame nozzle atthe outer end of the chamber which nozzle extends toward the maincombustion chamber of the engine, said ignition chamber being soconstructed and s aped as to form a space for accommodating the i iterpoints, which space is of regular tu ular formation-without an abruptexpansion immediately behind the orifice and it and the remainder of theigniltion c amber are 'of such roportions and shape, and so' situated,re atively to each other and to the main combustion chamber of theengine, that, during compression, only the auxiliary ignition stratifiedaroundthe 'i iter points, ;no turbulence being set up uring suchcompression to displace the auxiliary ignitionl charge clear from theigniter points.

charge 1s compressed An ignition device for internal-com around itsexterior which conoutlet chamber, an igniter therein, an inlet into saidchamber for an auxiliary ignition charge of explosive mixture, and aflame nozzle at the outer end of the chamber which nozzle extends towardthe main combustion chamber of the engine, a portion of said ignitionchamber being so constructed and shaped as to form a pocket foraccommodating the igniter Without an abrupt expansion immediately behindthe outlet ori-' fice, and said pocket and theremainder of the ignitionchamber being of such proportions and shape, and so situated, relativelyto each other and to the main combustion chamber of the engine,'that,during compression, only the auxiliary ignition charge is compressedStratified around the igniter, no turbulence being set upduring suchcompression to displace the auxiliary ignition charge clear from theigniter.

3. An ignition device for internal-combustion engines comprising anignition chamber, an electric igniter therein, an inlet .at the innerend of the chamber for an auxiliary ignition charge of explosivemixture, and an outwardly flaring flame nozzle at the outer end of thechamber which nozzle extends toward the maincombusti'on chamber of theengine, said ignition chamber being so constructed and shaped as to forma space for accommodating the igniter points, which space is of regulartubular formation without an abrupt expansion immediately behind theoutlet orifice, and it specified.

4. An ignition device for internal-combustion engines comprising anignition chamber, an electric igniter therein, an inlet at the inner endof the chamber for an auxiliary ignition char e of explosive mixture,andva flame nozz e at the outer end of the chamber which nozzle extendstoward the main combustion chamber of the engine, said ignition chamberbeing so constr'ucted and shaped as to form a space for accommodatingthe igniter points, which space, and the remainder of the igniter are ofsuch proportions and shape, and so situated, relatively to each otherand the main combustion chamber of the engine that, during compression,only the auxiliary ignition charge is compressed stratified around theigniter points, it (the auxiliary ignition charge) not being displacedclear therefrom by any part of the contents of the main enginecombustion chamber, for the purpose In testimon whereof I aflix mysignature. FRED RICK ARTHUR SMITH.

